Abstract
The recovery from cardiac surgery and cardiopulmonary bypass can be complicated by an acute inflammatory response. Circulating blood through an extracorporeal circuit (ECC) contributes to this complication. Perfluorocarbon-based blood substitutes (PFCs) are under investigation for use as a component of the ECC "prime" solution, because PFCs increase the oxygen-carrying capacity of the diluted blood. Some PFCs may provide the additional benefit of attenuating the ECC-induced inflammatory response. Earlier, we reported that perflubron emulsion (PFE, Alliance Pharmaceutical Corp.) reduced neutrophil (PMN) activation in vivo. However, the potential of PFE to reduce ECC-induced PMN activation has not been investigated. In this study, we used a small-scale ECC model to quantify the extent of PMN activation during circulation and to examine if PFE treatment attenuated PMN activation. ECC circuits were filled with a mixture of blood and Plasmalyte. Two groups were studied: an untreated group containing blood plus PlasmaLyte and a treated group in which some of the Plasmalyte was substituted with PFE (4.5 g/100 ml). Hematology and measures of whole blood PMN activation were made from blood samples taken periodically throughout the 120-min ECC circulation period. We found, for the untreated group, a significant decrease in the number of circulating PMNs and an increase in PMN activation with time. PMN activation was demonstrated as a significant increase in the expression of the PMN adhesion protein CD11b (P < 0.05) and an increase in PMN oxygen free radical production (reactive oxygen species (ROS)). After 120 min of circulation, the PMNs remained capable of a significant response to a second inflammatory stimulus, but PFE treatment significantly attenuated the fMLP-induced increase in PMN ROS at t = 120 min (P < 0.05). These results suggest that PFE may have dual utility in cardiac surgery, to increase oxygen delivery and to serve as an antiinflammatory agent.
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